Technique of tanning snake skins, and a material for painting and calligraphy produced by the technique

Abstract

The invention relates to a technique of tanning snake skins and a material for painting and calligraphy produced from such snake skins processed by the technique, taking snake skins as raw material. The products obtained by means of this technique are of clean and white in nature and having unique liquid penetrant quality, so that perfect material from commercial angle for painting and calligraphy can be manufactured out of these skins.

I claim: 
     
       1. A method of tanning snake skins, comprising the following steps: (1) introducing into a rotary drum for treating skins an amount of water weighing 15-27 times the weight of the skins to be processed, and sodium hydroxide weighing 1%-7% the weight of the skins;   (2) rotating the rotary drum for 1-30 minutes;   (3) introducing the skins into the rotary drum and leaving the contents therein undisturbed for 6-14 hours;   (4) discharging all the contents from the rotary drum;   (5) descaling the snake skins;   (6) weighing the skins;   (7) introducing into the rotary drum water weighing 5-7 times the weight of the skins weighed in step (6), and introducing into said drum a substance selected from the group consisting of: a) hydrogen peroxide at a concentration from 30%-70% of the weight of the skins in step (6), and   b) sodium hydrosulphite at a concentration from 2%-14% of the weight of the skins in step (6), and rotating the rotary drum for 1-30 minutes;     (8) introducing into the rotary drum the skins and leaving the contents therein undisturbed for 1.5-4 days;   (9) discharging the liquid from the rotary drum, and rinsing the contents in the drum to wash away the residual liquid;   (10) introducing into the rotary drum water weighing 5-7 times the weight of the skins weighed in step (6), and introducing at the same time a substance selected from the group consisting of: a) urea at a concentration from 6%-12% of the weight of the skins in step (6), and   b) ammonium sulphate at a concentration from 8%-17% of the weight of the skins in step (6); then rotating the rotary drum for 1-30 minutes and leaving the contents therein undisturbed for another 1-30 minutes;     (11) discharging the liquid from the rotary drum, and rinsing the contents in the drum to wash away the residual liquid;   (12) introducing into the rotary drum water weighing 5-7 times the weight of the skins weighed in step (6), and introducing at the same time furfurol weighing 6%-12% the weight of the skins in step (6), then rotating the rotary drum for 1-30 minutes and leaving the contents therein undisturbed for 2-4 hours;   (13) discharging the liquid from the rotary drum, and rinsing the contents in the drum to wash away the residual liquid;   (14) introducing into the rotary drum water weighing 5-7 times the weight of the skins weighed in step (6), and introducing at the same time salt weighing 20%-30% the weight of the skins in step (6), then rotating the rotary drum for 1-30 minutes and leaving the contents therein undisturbed for 1-30 minutes;   (15) also introducing into the rotary drum acetic acid weighing 8%-14% the weight of the skins in step (6), then rotating the rotary drum for 1-30 minutes and leaving the contents therein undisturbed 1-2 hours;   (16) discharging the liquid from the rotary drum, and rinsing the contents in the drum to wash away the residual liquid;   (17) introducing into the rotary drum water weighing 5-7 times the weight of the skins weighed in step (6), and introducing at the same time tannin of 1.5-2 degrees Be weighing 30%-60% the weight of the skins in step (6), then rotating the rotary drum for 1-30 minutes and leaving the contents therein undisturbed for 0.5-2 days;   (18) discharging the liquid from the rotary drum;   (19) introducing into the rotary drum water weighing 5-7 times the weight of the skins weighed in step (6), and introducing at the same time tannin of 2.5-3 degrees Be weighing 30%-60% the weight of the skins in step (6), then rotating the rotary drum for 1-30 minutes and leaving the contents therein undisturbed for 0.5-2 days;   (20) discharging the liquid from the rotary drum;   (21) introducing into the rotary drum water weighing 5-7 times the weight of the skins weighed in step (6), and introducing at the same time tannin of 5-6 degrees Be weighing 30%-60% the weight of the skins in step (6), then rotating the rotary drum for 1-30 minutes and leaving the contents therein undisturbed for 2-4 days;   (22) discharging from the rotary drum the whole contents; and   (23) drying in air the skins obtained from step (22).   
     
     
       2. A method of tanning snake skins as claimed in claim 1, wherein said step (1) is carried out in lukewarm water of 30° C.-60° C. weighing 20 times the weight of the skins to be processed, and the sodium hydroxide used in said step weighs 5% of the weight of the skins to be processed, and the time for leaving the contents undisturbed in step (3) is 8 hours. 
     
     
       3. A method of tanning snake skins as claimed in claim 1, wherein said step (7) is carried out in lukewarm water of 30° C.-60° C., and the time for leaving the contents undisturbed in step (8) is 2 days. 
     
     
       4. A method of tanning snake skins as claimed in claim 1, wherein said steps (17) and (19) are carried out in lukewarm water of 30° C.-60° C., and the time for leaving the contents undisturbed is 0.5 day. 
     
     
       5. A method of tanning snake skins as claimed in claim 1, wherein said step (21) is carried out in lukewarm water of 30° C.-60° C., and the time for leaving the contents undisturbed is 2 days.